Study finds vaccine
potency down with time
COVID-19 Vaccines remain effective, but
their potency has diminished in recent months, according to a study at eight
sites across the US. Scientists calculated vaccine effectiveness to be 80% in a
large group of fully vaccinated front-line workers between December 2020 and
August 2021, compared to 91% in earlier surveys.
The estimates were based on RY-PCR testing and did not measure whether there were changes in efficacy in protecting against severe disease, including hospitalisation and death. The Study say one reason for the change could be waning immunity, a decrease in the strength of the body's vaccine-activated defences against the virus. The difference may also reflect the fact that the vaccines are not as effective against the highly contagious Delta variant which, since June 2021,has become the most common cause of Covid-19 in the US.
The network followed 4,136 healthcare personnel, first
responders, and essential workers who had not previously had Covid-19. Study participants
submitted samples for RT-PCR testing on a weekly basis and 2,976 participants were
fully vaccinated within the study period, receiving the Pfizer-BioNtech (65%),
Moderna(33%),or Johnson & Johnson (2%) vaccines.
Best results from these groups
between December 14, 2020, to August 14,2021,show that: Among unvaccinated
study participants, 194 infections occurred in 181,357 person days (combined total
of number of days of testing for this group). Among fully vaccinated participants,
34 infections occurred in 454,832 person days. During that time period, the
vaccines were 80% effective for all fully vaccinated study participants, but preliminary
data indicate that vaccines may wane in intensity over time with lower
effectiveness after five or more months following full vaccination as per study.
Combo antibody treatment reduces hospitalization: study
In an observational study, Mayo Clinic researchers have
found that a combination of casirivimab and imdevimab — two monoclonal antibody
treatments that have emergency use authorisation from the
US Food and Drug Administration— keep high-risk patients out of the hospital
when infected with mild to moderate Covid-19.
Of the nearly 1400 Mayo Clinic patients enrolled
in this study, 696 received the drug combo between December 2020 and early
April. An equal number of patients didn't receive the drug combo. Upon
evaluation of their status at 14, 21 and 28 days after treatment, the numbers for
hospitalization were found to be significantly lower for the treated group, at
each stage.
At 14 days,
1.3% of the treated group was hospitalised, while 3.3 % of the non-treated
group was hospitalised. At day 21, the percentages of people hospitalised from
the treated and non-treated groups were 1.3 and4.2, respectively. At day 28,
1.6% of the treated patients were hospitalised compared to 4.8% of the
non-treated patients. From this data, it can be inferred that there was 60%-70%
relative reduction in hospitalization among treated patients.
The release quoted and study, as saying that when a
combination of monoclonal injections is used to treat patients who are at high
risk due to a range of comorbidities, and contract a mild or moderate case of
Covid- 19, they get an opportunity to recover without being hospitalised.
Our conclusion overall at this point is that
monoclonal antibodies are an important option in treatment to reduce the impact
of Covid-19 in high-risk patients, as per study.